Officials have blamed the attacks on clan fighters, Islamists and foreign terrorists.

Earlier, officials in Somalia's semi-autonomous Puntland region said local troops backed by U.S. naval forces killed at least eight Islamist fighters in the past two days.

Somali officials reported Saturday that a U.S. warship bombarded Islamist hideouts Friday and Saturday near the coastal town of Bargal. Puntland officials say the combined actions of local and U.S. forces "defeated" the Islamists, who had set up bases in the region over the past week.

U.S. Defense Secretary Robert Gates Sunday refused to comment on the events in Puntland, other than to say it was "possibly an ongoing operation."